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參數(shù)資料
| 型號： | DS1744P |
| 廠商： | DALLAS SEMICONDUCTOR |
| 元件分類： | Timer or RTC |
| 英文描述： | REAL TIME CLOCK, DMA34 |
| 封裝： | POWERCAP MODULE-34 |
| 文件頁數(shù)： | 13/18頁 |
| 文件大小： | 225K |
| 代理商： | DS1744P |
DS1744/DS1744P
4 of 18
DS1744TRUTH TABLE Table 1
VCC
CE
OE
WE
MODE
DQ
POWER
VIH
X
DESELECT
HIGH-Z
STANDBY
VIL
XVIL
WRITE
DATA IN
ACTIVE
VIL
VIH
READ
DATA OUT
ACTIVE
VCC>VPF
VIL
VIH
READ
HIGH-Z
ACTIVE
VSO<VCC<VPF
XXXDESELECT
HIGH-Z
CMOS STANDBY
VCC<VSO<VPF
XXXDESELECT
HIGH-Z
DATA RETENTION
MODE
SETTING THE CLOCK
As shown in Table 2, bit 7 of the century register is the write bit. Setting the write bit to a one, like the
read bit, halts updates to the DS1744 registers. The user can then load them with the correct day, date and
time data in 24 hour BCD format. Resetting the write bit to a zero then transfers those values to the actual
clock counters and allows normal operation to resume.
STOPPING AND STARTING THE CLOCK OSCILLATOR
The clock oscillator may be stopped at any time. To increase the shelf life, the oscillator can be turned off
to minimize current drain from the battery. The OSC bit is the MSB (bit 7) of the seconds registers, see
Table 2. Setting it to a one stops the oscillator.
FREQUENCY TEST BIT
As shown in Table 2, bit 6 of the day byte is the frequency test bit. When the frequency test bit is set to
logic “1” and the oscillator is running, the LSB of the seconds register will toggle at 512 Hz. When the
seconds register is being read, the DQ0 line will toggle at the 512 Hz frequency as long as conditions for
access remain valid (i.e., CE low, OE low, WE high, and address for seconds register remain valid and
stable).
CLOCK ACCURACY (DIP MODULE)
The DS1744 is guaranteed to keep time accuracy to within
±1 minute per month at 25°C. The RTC is
calibrated at the factory by Dallas Semiconductor using nonvolatile tuning elements, and does not require
additional calibration.
For this reason, methods of field clock calibration are not available and not
necessary.
Clock accuracy is also effected by the electrical environment and caution should be taken to
place the RTC in the lowest level EMI section of the PCB layout. For additional information please see
application note 58.
CLOCK ACCURACY (POWERCAP MODULE)
The DS1744 and DS9034PCX are each individually tested for accuracy. Once mounted together, the
module will typically keep time accuracy to within
±1.53 minutes per month (35 ppm) at 25°C. Clock
accuracy is also effected by the electrical environment and caution should be taken to place the RTC in the
lowest level EMI section of the PCB layout. For additional information please see application note 58.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| DS1744 | REAL TIME CLOCK, DMA28 |
| DS1746-70 | 0 TIMER(S), REAL TIME CLOCK, DIP32 |
| DS1746WP-120 | 0 TIMER(S), REAL TIME CLOCK, DMA34 |
| DS1746W-120 | 0 TIMER(S), REAL TIME CLOCK, DIP32 |
| DS1746P-70 | 0 TIMER(S), REAL TIME CLOCK, DMA34 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS1744P/YP/WP | 制造商:MAXIM 制造商全稱:Maxim Integrated Products 功能描述:PowerCap with Crystal |
| DS1744P-70 | 功能描述:實時時鐘 RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時間格式:HH:MM:SS RTC 存儲容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
| DS1744P-70+ | 功能描述:實時時鐘 Timekeeping NV RAM RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時間格式:HH:MM:SS RTC 存儲容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
| DS1744P-70IND | 功能描述:實時時鐘 RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時間格式:HH:MM:SS RTC 存儲容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
| DS1744P-70IND+ | 功能描述:實時時鐘 Timekeeping NV RAM RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時間格式:HH:MM:SS RTC 存儲容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
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